Compact bearing assemblies including superhard bearing surfaces, bearing apparatuses, and methods of use

ABSTRACT

Embodiments of the invention are directed to compact bearing assemblies configured to operate in small spaces and/or in harsh environments, bearing apparatuses including such bearing assemblies, and method of operating such bearing assemblies and apparatuses. For instance, one or more compact bearing assemblies may at least partially rotatably secure a shaft of a power generation unit to a housing thereof. Also, a first compact bearing assembly may connect or couple to the shaft and may rotatably engage a second compact bearing assembly, which may be connected or otherwise secured to the housing.

BACKGROUND

Subterranean drilling systems can employ various tools that requireelectrical power. In some instances, a drilling system includes a powergeneration unit. Fluid, such as drilling fluid, may flow through aturbine of the power generation unit, thereby producing rotation of ashaft, which may be converted into electrical power (e.g., the powergeneration unit may drive an alternator). Bearing apparatuses (e.g.,thrust, radial, tapered, and other types of bearings) also may beoperably coupled to the shaft and may assist in maintaining the shaft ina substantially stationary lateral and/or axial position, for instance,relative to a housing, while allowing the shaft to rotate.

A typical bearing apparatus includes a stator that does not rotate and arotor that is attached to the shaft and rotates with the shaft. Theoperational lifetime of the bearing apparatuses often determines theuseful life of the power generation unit as well as of the subterraneandrilling system. Therefore, manufacturers and users of subterraneandrilling systems and power generation units continue to seek improvedbearing apparatuses to extend the useful life of such bearingapparatuses.

SUMMARY

Embodiments of the invention are directed to compact bearing assembliesconfigured to operate in small spaces and/or in harsh environments,bearing apparatuses including such bearing assemblies, and methods ofoperating such bearing assemblies and apparatuses. For instance, one ormore compact bearing assemblies may at least partially rotatably securea shaft of a power generation unit to a housing thereof. In anembodiment, a first compact bearing assembly may connect or couple tothe shaft and may rotatably engage a second compact bearing assembly,which may be connected or otherwise secured to the housing. Furthermore,when engaged with one another, the first and second compact bearingassemblies may have limited or no lateral movement relative to oneanother. Hence, a bearing apparatus that may include the first andsecond bearing assemblies may rotatably secure the shaft to the housing,while limiting lateral movement of the shaft relative to the housing.

An embodiment includes a bearing apparatus including a first bearingassembly and a second bearing assembly. The first bearing assemblyincludes a first support structure. The first bearing assembly furtherincludes a first superhard body secured to the first support structureand protruding above a top surface thereof and defining a convexradial-bearing surface. The second bearing assembly includes a secondsuperhard body secured within the recess. In addition, the secondsuperhard body includes an opening defined by a concave radial-bearingsurface that is sized and configured to rotatably engage the firstradial-bearing surface.

Embodiments also include a power generation unit including a housing anda first bearing assembly attached to the housing. The first radialbearing assembly includes a first single superhard body that defines afirst radial-bearing surface. The power generation unit also includes ashaft rotatably secured within the housing in a manner that flow offluid through the power generation unit produces rotation of the shaft.Furthermore, the power generation unit includes a second bearingassembly attached to the shaft. The second bearing assembly includes asecond single superhard body that defines a second radial-bearingsurface, the second radial-bearing surface being rotatably engaged withthe first radial-bearing surface. In addition, the power generation unitincludes an alternator operably connected to the shaft.

Another embodiment is directed to a method of rotating a shaft within ahousing. The method includes attaching a first bearing assembly to theshaft and attaching a second bearing assembly to the housing.Additionally, the method includes positioning a first radial-bearingsurface of the first bearing assembly inside an opening defined by asecond radial-bearing surface of the second bearing assembly. Moreover,one or more of the first radial-bearing surface or the secondradial-bearing surface include superhard material. The method alsoincludes forming a fluid film between the first radial-bearing surfaceand the second radial-bearing surface during the rotation of the shaftwithin the housing, thereby producing hydrodynamic operation between thefirst radial-bearing surface and the second radial-bearing surface.

Features from any of the disclosed embodiments may be used incombination with one another, without limitation. In addition, otherfeatures and advantages of the present disclosure will become apparentto those of ordinary skill in the art through consideration of thefollowing detailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate several embodiments of the present disclosure,wherein identical reference numerals refer to identical or similarelements or features in different views or embodiments shown in thedrawings.

FIG. 1A is an isometric view of a first bearing assembly according to anembodiment;

FIG. 1B is a cross-sectional view of the first bearing assembly of FIG.1A;

FIG. 1C is an isometric view of a first bearing assembly according toanother embodiment;

FIG. 2A is a cross-sectional view of a second bearing assembly accordingto an embodiment;

FIG. 2B is a cross-sectional view of a second bearing assembly accordingto another embodiment;

FIG. 2C is a cross-sectional view of a second bearing assembly accordingto yet another embodiment;

FIG. 3A is a cross-sectional view of a bearing apparatus according to anembodiment;

FIG. 3B is a cross-sectional view of a bearing apparatus according toanother embodiment;

FIG. 3C is a cross-sectional view of a bearing apparatus according toyet another embodiment;

FIG. 3D is a cross-sectional view of a bearing apparatus according tostill one other embodiment; and

FIG. 4 is a partial cross-sectional view of a power generation unitaccording to an embodiment.

DETAILED DESCRIPTION

Embodiments of the invention are directed to compact bearing assembliesconfigured to operate in small spaces and/or in harsh environments,bearing apparatuses including such bearing assemblies, and method ofoperating such bearing assemblies and apparatuses. For instance, one ormore compact bearing assemblies may at least partially rotatably securea shaft of a power generation unit to a housing thereof. In anembodiment, a first compact bearing assembly may connect or couple tothe shaft and may rotatably engage a second compact bearing assembly,which may be connected or otherwise secured to the housing. Furthermore,when engaged with one another, the first and second compact bearingassemblies may have limited or no lateral movement relative to oneanother. Hence, a bearing apparatus that may include the first andsecond bearing assemblies may rotatably secure the shaft to the housing,while limiting lateral movement of the shaft relative to the housing.

In an embodiment, one of the first bearing assembly and the secondbearing assembly may include a protrusion that may have a convexsubstantially cylindrical bearing surface, while the other of the firstand second bearing assemblies may include an opening defined by aconcave substantially cylindrical bearing surface that may rotatablyengage the protrusion. As such, the first bearing assembly may rotaterelative to the second bearing assembly, as described above. Inadditional or alternative embodiments, the first and/or the secondbearing assembly may include superhard material that may form or defineat least a portion of the bearing surfaces thereof. For example, thefirst and/or second bearing assembly may include a superhard body bondedto a substrate. The respective superhard bodies may include superhardmaterial that forms/defines bearing surfaces of the first and secondbearing assemblies.

In some embodiments, the first bearing assembly may include a superhardbody that protrudes away from the support structure, thereby forming aprotrusion with a convex bearing surface that may enter and/or engagethe second bearing assembly. For example, the second bearing assemblymay include an interior surface that may form/define a concave bearingsurface of the second bearing assembly. For example, the protrusion ofthe first bearing assembly may enter an opening in the second bearingassembly and may engage the bearing surface of the second bearingassembly.

Furthermore, as noted above, in an embodiment, the respective bearingsurfaces of the first and second bearing assemblies may beformed/defined by superhard material (e.g., superhard material ofrespective superhard bodies). As such, the bearing surface defined orformed by the opening in the second bearing assembly may includesuperhard material. In an embodiment, the superhard material may be abody of superhard material mounted on or within the support structure.Such superhard body may form a hole or an opening that may rotatably atleast partially engage the protrusion of the first bearing assembly.

Also, in some embodiments, the first bearing assembly may be a rotor,while the second bearing assembly may be a stator (e.g., the secondbearing assembly may be substantially stationary relative to a housingor other machine component, while the first bearing assembly may rotatetogether with the shaft) or vice versa. In any event, at least a portionof a protrusion of the first bearing assembly may rotatably at leastpartially engage an opening in the second bearing assembly in a mannerthat allows the first and second bearing assemblies to rotate relativeto each other, while preventing or limiting lateral movement thereof.

FIGS. 1A-1C illustrate an embodiment of a first bearing assembly 100.The first bearing assembly 100 may include a first radial-bearingsurface 110, which may at least partially engage a corresponding bearingsurface of the second bearing assembly, as described below in moredetail.

In an embodiment, the first radial-bearing surface 110 may be convex andapproximately cylindrical. Furthermore, in some instance, the firstradial-bearing surface 110 may be substantially continuous oruninterrupted. Accordingly, rotation of the first radial-bearing surface110 about an axis 10 may cause the first radial-bearing surface 110 tobe in at least partial contact with the opposing bearing surface of thesecond bearing assembly. Alternatively, however, the firstradial-bearing surface 110 may be discontinuous and/or interrupted(e.g., the first radial-bearing surface 110 may include groove).

Additionally, the first radial-bearing surface 110 may include superhardmaterial, such that the first radial-bearing surface 110 may exhibit ahardness that is at least as hard as tungsten carbide. In any of theembodiments disclosed herein, the superhard material may include one ormore of polycrystalline diamond, polycrystalline cubic boron nitride,silicon carbide, tungsten carbide, or any combination of the foregoingsuperhard materials.

For instance, the first bearing assembly 100 may have a superhard body120 that may include the first radial-bearing surface 110. Particularly,a peripheral surface of the superhard body 120 may form/define the firstradial-bearing surface 110. In addition, the superhard body 120 mayinclude a chamfer 121 extending between the first radial-bearing surface110 and a top surface 122 of the superhard body 120. Under someoperating conditions, the chamfer 121 may prevent or eliminate chippingof the superhard body 120 that may, otherwise, affect continuity of thefirst radial-bearing surface 110.

In an embodiment, the superhard body 120 may be bonded to a substrate130, which may be secured to a support structure 140. The supportstructure 140 may have any suitable shape, which may vary from oneembodiment to the next. In an embodiment, the support structure 140 mayhave a generally cylindrical shape. Moreover, the support structure 140may include multiple sections connected together or integrated with oneanother, such as sections 141, 142, and 143. Thickness of each section(as measured along the axis 10) as well as the overall thickness of thesupport structure 140 may vary one embodiment to another, and may dependon a particular application and load experienced by the supportstructure 140, among other factors or considerations.

Similarly, as mentioned above, the shapes of the sections 141, 142, 143may vary depending on particular application of the first bearingassembly 100. In some instances, the peripheral surface of the section141 may have one or more flat or planar portions, which may facilitateengagement of a tool therewith (e.g., a wrench may engage the planarportions(s) in a manner that allows the tool to rotate the supportstructure 140 about the axis 10). For example the section 141 may be ahexagonal prismoid. Additionally or alternatively, the section 141 mayhave at least partially cylindrical shape (e.g., in high speed operationa cylindrical shape may improve balance of the first bearing assembly100 and/or reduce vibration thereof). In any event, a tool may be usedto hold and/or assemble the first bearing assembly 100 for operation(e.g., to rotate the first bearing assembly 100 such as to screw thefirst bearing assembly 100 onto a shaft).

In some embodiments, the sections 142, 143 may have approximatelycylindrical shapes. Moreover, in an embodiment, the sections 142 and 143may have dissimilar diameters and/or thicknesses. For example, theoutside diameter of section 142 may be larger than the outside diameterof section 143. Moreover, in some instances, the section 143 may atleast partially enter an opening in the second bearing assembly, whilethe section 142 may be larger than such opening. Likewise, the section141 may be larger than section 142, such as to provide sufficientsurface area for engaging a tool that may be used to secure the firstbearing assembly 100 to a shaft (as discussed in greater detailhereinbelow).

Furthermore, in an embodiment, one, some, or all of the sections 141,142, 143 may be generally concentric with one another. For instance, thesections 141, 142, 143 may be substantially centered about the axis 10.Alternatively, however, some or all of the sections 141, 142, 143 may beoff-center relative to one another. In addition, one or more of thesections may include an opening, such as an opening 144 in the section141, which may accept a shaft and/or a fastener that may secure thefirst bearing assembly 100 to a machine element or component.

As described above, the first bearing assembly 100 may include thesuperhard body 120 that may be bonded to the substrate 130. For example,the superhard body 120 may comprise polycrystalline diamond and thesubstrate 130 may comprise cobalt-cemented tungsten carbide. Othercarbide materials may be used with tungsten carbide or as analternative, such as chromium carbide, tantalum carbide, vanadiumcarbide, titanium carbide, or combinations thereof cemented with iron,nickel, cobalt, or alloys thereof. Furthermore, in any of theembodiments disclosed herein, the polycrystalline diamond body may beleached to at least partially remove or substantially completely removea metal-solvent catalyst (e.g., cobalt, iron, nickel, or alloys thereof)that was used to initially sinter precursor diamond particles to formthe polycrystalline diamond. In another embodiment, an infiltrant usedto re-infiltrate a preformed leached polycrystalline diamond body may beleached or otherwise at least partially removed to a selected depth froma bearing surface. Moreover, in any of the embodiments disclosed herein,the polycrystalline diamond may be un-leached and include ametal-solvent catalyst (e.g., cobalt, iron, nickel, or alloys thereof)that was used to initially sinter the precursor diamond particles thatform the polycrystalline diamond and/or an infiltrant used tore-infiltrate a preformed leached polycrystalline diamond body. Examplesof methods for fabricating the superhard bearing elements and superhardmaterials and/or structures from which the superhard bearing elementsmay be made are disclosed in U.S. Pat. Nos. 7,866,418; 7,998,573;8,034,136; and 8,236,074; the disclosure of each of the foregoingpatents is incorporated herein, in its entirety, by this reference.

The diamond particles that may be used to fabricate the superhard body150 a in a high-pressure/high-temperature process (“HPHT”) may exhibit alarger size and at least one relatively smaller size. As used herein,the phrases “relatively larger” and “relatively smaller” refer toparticle sizes (by any suitable method) that differ by at least a factorof two (e.g., 30 μm and 15 μm). According to various embodiments, thediamond particles may include a portion exhibiting a relatively largersize (e.g., 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, 15 μm, 12 μm, 10μm, 8 μm) and another portion exhibiting at least one relatively smallersize (e.g., 15 μm, 12 μm, 10 μm, 8 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than 0.1 μm). In anembodiment, the diamond particles may include a portion exhibiting arelatively larger size between about 10 μm and about 40 μm and anotherportion exhibiting a relatively smaller size between about 1 μm and 4μm. In another embodiment, the diamond particles may include a portionexhibiting the relatively larger size between about 15 μm and about 50μm and another portion exhibiting the relatively smaller size betweenabout 5 μm and about 15 μm. In another embodiment, the relatively largersize diamond particles may have a ratio to the relatively smaller sizediamond particles of at least 1.5. In some embodiments, the diamondparticles may comprise three or more different sizes (e.g., onerelatively larger size and two or more relatively smaller sizes),without limitation. The resulting polycrystalline diamond orsuperabrasive body formed from HPHT sintering the aforementioned diamondparticles may also exhibit the same or similar diamond grain sizedistributions and/or sizes as the aforementioned diamond particledistributions and particle sizes. Such polycrystalline diamond includesa plurality of diamond grains exhibiting diamond-to-diamond bonding(e.g., sp³ bonding) therebetween and defining interstitial regionshaving a catalyst therein (e.g., a metal-solvent catalyst or carbonatecatalyst). Other superabrasive/superhard materials may include aplurality of superabrasive grains bonded together to define interstitialregions having a catalyst therein. Additionally, in any of theembodiments disclosed herein, the superhard bearing elements may befree-standing (e.g., substrateless) and optionally may be at leastpartially leached or fully leached to remove a metal-solvent catalystinitially used to sinter the polycrystalline diamond body.

In some embodiments, the substrate 130 may be secured within the supportstructure 140. For example, the support structure 140 may include arecess 145 that can at least partially accommodate the substrate 130therein. As such, at least a portion of the substrate 130 may bepositioned and secured within the recess 145. In an embodiment, therecess 145 may be generally concentric with the opening 144. Hence, therecess 145 may generally concentrically locate the substrate 130relative to the opening 144. For instance, the recess 145 may becentered about the axis 10.

Furthermore, the superhard body 120 may be generally concentric withinthe substrate 130. For example, the first radial-bearing surface 110 ofthe superhard body 120 may be centered about the axis 10. Thus, in oneor more embodiments, the first radial-bearing surface 110 may begenerally concentric with the opening 144, such that rotation of theshaft secured within the opening 144 may produce a rotation of the firstbearing assembly 100 during which the first radial-bearing surface 110rotates approximately concentrically within the support structure 140and/or with the shaft.

In an embodiment, the recess 145 may be approximately cylindrical (i.e.,may have an approximately circular cross-section). Likewise, thesubstrate 130 may have approximately cylindrical cross-section and mayhave a similar size to the recess 145. For example, the recess 145 mayhave sufficient clearance to accommodate the substrate 130 therein. Thesubstrate 130 may be brazed, soldered, welded, fastened, press-fit, orotherwise secured to the support structure 140 (e.g., within the recess145). It should be also appreciated that the recess 145 may have anysuitable shape, which may vary from one embodiment to the next.Correspondingly, the substrate 130 also may have any suitable shape thatmay be mountable inside the recess 145. In any event, the superhard body120 may be secured to or incorporated with the support structure 140.Thus, rotation of the first bearing assembly 100 may produce acorresponding rotation of the first radial-bearing surface 110, whichmay be approximately concentrically aligned with the axis of rotation ofthe shaft.

In some embodiments, the clearance between the recess 145 and thesubstrate 130 may be substantially small to allow final finishing of thefirst radial-bearing surface 110 before securing the substrate 130within the recess 145. Additionally or alternatively, the substrate 130may be first secured within the recess 145, and the first radial-bearingsurface 110 may be finished (e.g., ground) thereafter. Similarly, in anembodiment, the top surface 122 of the superhard body 120 also may befinished after securing the substrate 130 in the recess 145. In anembodiment, the top surface 122 also may be unfinished or may befinished before securing the substrate 130 to the support structure 140.

In some embodiments, the substrate 130 may protrude above a top surface146 (FIG. 1B) of the support structure 140. Alternatively, the substrate130 may be entirely within the support structure 140, such that aninterface between the substrate 130 and superhard body 120 may belocated approximately in plane with top surface 146. In any case, in oneor more embodiments, the superhard body 120 may be located entirelyabove the top surface 146 of the support structure 140. In otherembodiments, the superhard body 120 may be partially located in therecess 145.

Referring still to FIG. 1B, in an embodiment, the superhard body 120 mayhave a thickness 123 (measured from the substrate 130 to the top surface122) that is similar to or the same as the height of the substrate 130.For example, the thickness of the superhard body 120 may beapproximately 0.25 inches, while the thickness of the substrate 130 maybe between 0.23 inches to 0.27 inches. Additional examples of suitablethicknesses of the superhard body 120 and/or substrate 130 may includethe following: about 0.05 inches to about 0.10 inches; about 0.08 inchesto about 0.15 inches; about 0.12 inches to about 0.2 inches; about 0.18inches to about 0.25 inches; about 0.20 inches to about 0.30 inches; orabout 0.25 inches to about 0.50 inches. It should be appreciated thatthe superhard body 120 and/or substrate 130 may be thicker than 0.50inches or thinner than 0.08 inches.

It should be appreciated that in some embodiments, the superhard body120 may be bonded directly to the support structure 140. For example,the support structure 140 may comprise stainless steel and asubstrateless superhard body 120 may be brazed, press-fitted, orotherwise attached directly to the support structure 140. Alternatively,the support structure 140 may comprise tungsten carbide, and thesuperhard body 120 may be bonded to the support structure 140 (e.g.,using HPHT process described above). In any event, the first bearingassembly 100 may include the first radial-bearing surface 110,formed/defined by the superhard body 120, which may engage thecorresponding second radial-bearing surface of the second bearingassembly.

Moreover, in an embodiment, the first bearing assembly 100 may include athrust-bearing surface. In particular, the first radial-bearing surface110 may carry a radial load, thereby preventing or limiting lateralmovement of the shaft, for example, relative to the housing, while thethrust-bearing surface may prevent or limit axial movement of the shaftduring rotation thereof. For instance, the top surface 146 of thesupport structure 140 may be a thrust-bearing surface and may engage anopposing or corresponding thrust-bearing surface of the second bearingassembly or of another (e.g., third) bearing assembly. Furthermore, thetop surface 146 may include superhard material, such as polycrystallinediamond, which may be bonded or otherwise secured thereto.

As noted above, the first bearing assembly may include one or moregroves on a bearing surface thereof. For example, as illustrated in FIG.1C, a first bearing assembly 100 a may include a bearing surface 110 aformed by a superhard body 120 a, which includes a plurality of grooves111 a. Except as otherwise described below, the first bearing assembly100 a and its materials, elements, and components may be similar to orthe same as materials, elements, or components of the first bearingassembly 100 (FIGS. 1A and 1B).

In an embodiment, the grooves 111 a may be approximately parallel to theaxis 10 and may be spaced and arranged thereabout. For instance, thegrooves 111 a may be evenly spaced about the bearing surface 110 a, suchthat the distance between any two adjacent grooves 111 a is the same asthe distance between any two other adjacent grooves 111 a. It should beappreciated, however, that the bearing surface 110 a may include anynumber of grooves, which may have any suitable size, orientation (e.g.,horizontal), configuration (e.g., spiral, arcuate, etc.), andcombinations thereof.

As mentioned above, the first bearing assembly 100 may rotatably engagethe second bearing assembly. FIG. 2A illustrates an embodiment of asecond bearing assembly 200. Generally, except as otherwise describedbelow, the second bearing assembly 200 and its materials, elements, andcomponents may be similar to or the same as materials, elements, orcomponents of the first bearing assembly 100 (FIGS. 1A and 1B). In someembodiments, a superhard body 220 and/or a substrate 230 of the secondbearing assembly 200 may include materials similar to or the same as thesuperhard body 120 and substrate 130, respectively. Also, in oneexample, the second bearing assembly 200 may include a secondradial-bearing surface 210, which may engage the first radial-bearingsurface 110 (FIGS. 1A and 1B). Embodiments may include the superhardbody 220 that may form or define the second radial-bearing surface 210.The superhard body 220 may be bonded to the substrate 230, which may besecured to a support structure 240.

The second radial-bearing surface 210 may have a concave andapproximately cylindrical shape that may span about an axis 10 a in amanner that defines an opening in the second bearing assembly 200.Particularly, the cylindrical shape of the second radial-bearing surface210 may at least partially engage the corresponding first radial-bearingsurface of the first bearing assembly. In other words, the protrudingsuperhard body that may form/define the first radial-bearing surface maybe positioned at least partially within an opening 211 in the secondbearing assembly 200 and the first radial-bearing surface may at leastpartially contact the second radial-bearing surface 210. In someinstances, the opening 211 may have an approximately cylindrical shape,such as to define an inside diameter 224.

When at least partially engaged, the first radial-bearing surface andthe second radial-bearing surface 210 may be substantially concentricwith each other, such that the axis 10 a is generally aligned with theaxis 10 (FIGS. 1A and 1B). In any event, the first radial-bearingsurface 110 (FIGS. 1A and 1B) may at least partially contact the secondradial-bearing surface 210, such that the second bearing assembly 200and the first bearing assembly may rotate relative to each other withlimited relative lateral movement. In some embodiments, the secondradial-bearing surface 210 may be substantially continuous.Alternatively, the second radial-bearing surface 210 may have groves orother interruptions (e.g., to supply fluid between the secondradial-bearing surface 210 and the first radial-bearing surface).

In an embodiment, the support structure 240 may have an approximatelycylindrical shape. Furthermore, the support structure 240 may include arecess 241 that may secure the superhard body 220 and/or the substrate230 therein. The superhard body 220 and/or substrate 230 may bepress-fitted, brazed, fastened, or otherwise secured in the recess 241.Moreover, the second bearing assembly 200 may include the superhard body220 that is substrateless, which may be bonded or otherwise secureddirectly to the support structure 240. In any event, the superhard body220 may be secured to the support structure 240 and may have a suitableshape and size that may allow the first radial-bearing surface to atleast partially enter the opening 211 formed in the superhard body 220as well as at least partially contact the second radial-bearing surface210. In another embodiment, the substrate 230 may be an annularsubstrate (e.g., ring-shaped) that is attached to the support structure240 and the superhard body 220 may be received by and bonded with theannular substrate.

As shown in FIG. 2A, the second bearing assembly 200 may include athrough hole 250. In some instances, the through hole 250 may allowfluid (e.g., drilling fluid) to enter and/or exit the second bearingassembly 200. For instance, the through hole 250 may be in fluidcommunication with the opening 211 defined by the second radial-bearingsurface 210. Furthermore, any debris or dust generated during operationof the second bearing assembly 200 and the first bearing assembly mayexit through the through hole 250, which may reduce wear of the secondradial-bearing surface 210 and/or of the first radial-bearing surface.Moreover, the through hole 250 may include a female thread, which may beaccept a fastener that may secure the second bearing assembly 200 to amachine element or component.

In some instances, the second bearing assembly 200 may include a chamfer260 extending between a peripheral surface thereof and a top surface270. Additionally or alternatively, the second bearing assembly 200 mayinclude a second chamfer or lead-in 280, which may extend between thetop surface 270 and a peripheral surface of the recess 241. The chamfer260 and/or lead-in 280 may reduce or eliminate chipping or breaking ofotherwise sharp corners or edges of the second bearing assembly 200.

In an embodiment, the top surface of the superhard body 220 also mayform/define a thrust-bearing surface 221, which may at least partiallycontact the thrust-bearing surface of the first bearing assembly tolimit or prevent relative axial movement of the first and second bearingassemblies. Hence, in one or more embodiments, the thrust-bearingsurface 221 may include superhard material, such as polycrystallinediamond.

In some embodiments, the superhard body may include a chamfer to preventchipping or cracking thereof during assembly and/or operation. Forinstance, FIG. 2B illustrates a second bearing assembly 200 a thatincludes a superhard body 220 a, which has a bearing surface 210 a, andwhich may be bonded to a substrate 230 a. Except as otherwise describedherein, the second bearing assembly 200 a and its materials, elements,and components may be similar to or the same as materials, elements, orcomponents of the second bearing assembly 200 (FIG. 2A). In anembodiment, the superhard body 220 a may include a chamfer 222 a, whichmay be positioned at the top of an opening 211 a defined by the bearingsurface 210 a.

In additional or alternative embodiments, the second bearing assemblymay include grooves, which may be similar to or the same as the groovesof the first bearing assembly. For example, FIG. 2C illustrates a secondbearing assembly 200 b that has a superhard body 220 b that forms ordefines a bearing surface 210 a, and which includes a plurality ofgrooves 212 b. Except as otherwise described herein, the second bearingassembly 200 b and its materials, elements, and components may besimilar to or the same as materials, elements, or components of any ofthe second bearing assemblies 200, 200 a (FIGS. 2A and 2B). In someembodiments, the grooves 212 b may extend into and through a substrate230 b. Accordingly, for example, fluid may flow through the groove 212 band into and/or out of an opening 211 b of the second bearing assembly200 b. Moreover, it should be appreciated, however, that the bearingsurface 210 b may include any number of grooves, which may have anysuitable size, orientation (e.g., horizontal), configuration (e.g.,spiral, arcuate, etc.), and combinations thereof.

As noted above, the first and second bearing assemblies rotate withrespect to one another, wherein the first radial-bearing surface and thesecond radial-bearing surface 210 at least partially contact oneanother. FIG. 3A illustrates an embodiment of a bearing apparatus 300that includes the first bearing assembly 100 and second bearing assembly200 assembled with one another. In some embodiments, the first bearingassembly 100 may be a rotor, while the second bearing assembly 200 maybe a stator. Alternatively, the first bearing assembly 100 may be astator, while the second bearing assembly 200 may be a rotor (e.g., thesecond bearing assembly 200 may be attached to the shaft). Furthermore,in an embodiment, both the first bearing assembly 100 and the secondbearing assembly 200 may rotate relative to a machine or mechanismincorporating the bearing apparatus 300. In any case, the first bearingassembly 100 and second bearing assembly 200 may rotate relative to oneanother.

Particularly, the superhard body 120 may be positioned at leastpartially within the opening in the second bearing assembly 200 definedby the superhard body 220. As mentioned above, the superhard body 220and the superhard body 120 may at least partially contact one another,thereby providing a rotatable bearing between the first bearing assembly100 and the second bearing assembly 200. In some embodiments, diameter124 of the superhard body 120 may be sufficiently small to accommodatecompact spaces. For instance, the diameter 124 of the superhard body 120may be in one or more of the following ranges: about 0.08 inches to 0.15inches; about 0.10 inches to 0.20 inches; about 0.18 inches to about0.38 inches; about 0.30 inches to 0.50 inches; about 0.40 inches to 0.80inches; less than 2 inches; or less than 1 inch. In some instances, thediameter 124 of the superhard body 120 may be smaller than 0.08 inchesor greater than 0.80 inches.

Similarly, the superhard body 120 may have a suitable thickness 123,which may vary from one embodiment to another. For example, thethickness 123 of the superhard body 120 may be in one or more of thefollowing ranges: about 0.05 inches to about 0.09 inches; about 0.08inches to about 0.12 inches; about 0.09 inches to about 0.15 inches;about 0.15 inches to about 0.25 inches; less than 0.15 inches; less than0.20 inches; or less than 0.50 inches. It should be appreciated that insome embodiments, the thickness 123 may be less than 0.05 inches orgreater than 0.50 inches.

As mentioned above, the second radial-bearing surface 210 may define anopening that is sufficiently shaped and sized to accept and at leastpartially contact the first radial-bearing surface 110 during operation(e.g., the opening may have the diameter 224). Furthermore, in someembodiments, the bearing apparatus 300 may include a clearance or a gapbetween the first radial-bearing surface 110 and the secondradial-bearing surface 210 (measured by the difference between theoutside diameter defined by the first radial-bearing surface 110 andinside diameter defined by the second radial-bearing surface 210). Forexample, the gap between the first radial-bearing surface 110 and thesecond radial-bearing surface 210 may be in one or more of the followingranges (provided as a percentage of the diameter defined by the firstradial-bearing surface 110): about 0.5% to 1.0%; about 0.8% to 1.5%;about 1.2% to 2.5%; about 2% to 3%; or about 2.7% to 3.5%. In someinstances, the gap between the first radial-bearing surface 110 and thesecond radial-bearing surface 210 may be less than 0.5% or greater than3.5% of the diameter defined by the first radial-bearing surface 110. Ina specific embodiment, the first radial-bearing surface 110 may definean outside diameter of about 0.249 inches, while the secondradial-bearing surface 210 may define an inside diameter of about 0.256inches, forming a gap of about 0.007 inches.

Although the gap of about 0.007 inches may be atypical for radialbearing assemblies, such gap may facilitate development of fluid filmbetween the first radial-bearing surface 110 and the secondradial-bearing surface 210, thereby producing a hydrodynamic operationof the bearing apparatus 300. In some instances, the fluid may beintroduced between the first radial-bearing surface 110 and the secondradial-bearing surface 210 through a space 310 between the first bearingassembly 100 and the second bearing assembly 200. Alternatively, thefluid may be introduced through the through hole 250 in the secondbearing assembly 200. It should be also appreciated that the fluid maybe introduced between the first radial-bearing surface 110 and secondradial-bearing surface 210 in any number of suitable ways, which mayvary from one embodiment to the next. Additionally, in some embodimentsthe drilling fluid may be channeled to enter the space between the firstradial-bearing surface 110 and second radial-bearing surface 210 and mayform the fluid film, which may facilitate hydrodynamic operation of thebearing apparatus 300.

In some embodiments, a portion of the substrate 130 may be positioned atleast partially within the opening defined by the second radial-bearingsurface 210. Alternatively, the substrate 130 may be outside of or abovethe opening formed by the second radial-bearing surface 210 and may notcontact the second radial-bearing surface 210 during operation of thebearing apparatus 300. Accordingly, the substrate 130 may not experiencewear during operation of the bearing apparatus 300.

In addition, as mentioned above, the chamfer 121 may prevent thesuperhard body 120 from chipping and/or cracking during the operation ofthe bearing apparatus 300. Moreover, in some embodiments, the chamfer121 may start below the second radial-bearing surface 210. As such, insome embodiments, the entire first radial-bearing surface 110 may be incontact with the second radial-bearing surface 210.

In some embodiments, the bearing apparatus may carry both a radial loadand a thrust load. For instance, as illustrated in FIG. 3B, a bearingapparatus 300 a may include opposing thrust-bearing surfaces 115 a, 215a of first and second bearing assemblies 100 a, 200 a. Except asotherwise described herein, materials, elements, or components of thebearing apparatus 300 a may be similar to or the same as materials,elements, or components of the bearing apparatus 300 (FIG. 3A). Forinstance, the first and second bearing assemblies 100 a, 200 a also mayinclude radial bearing surfaces 110 a, 210 a that may carry the radialload exerted onto the bearing apparatus 300 a.

Moreover, in an embodiment, both the thrust-bearing surface 115 a andthe radial bearing surface 110 a may be formed by the same superhardbody 120 a of the first bearing assembly 100 a. In an embodiment, thesuperhard body 120 a may be bonded to a substrate 130 a. Thethrust-bearing surface 215 a and the radial bearing surface 210 a of thesecond bearing assembly 200 a may be formed/defined by a superhard body220 a. In some instance, the superhard body 220 a may be bonded directlyto a support structure 240.

As noted above, bearing surfaces of the first and/or second bearingassembly may include one or more grooves therein. For example, FIG. 3Cillustrates a bearing apparatus 300 b that includes a first bearingassembly 100 b and a second bearing assembly 200 b, either or both ofwhich may include grooves in the bearing surfaces thereof. Inparticular, an embodiment includes grooves 211 b in a superhard body 220b of the second bearing assembly 200 b. It should be also appreciatedthat, in one or more embodiments, the first bearing assembly 100 b alsomay include grooves in the bearing surface thereof (e.g., as describedabove in connection with FIG. 1C).

In any event, fluid may be circulated through one or more grooves in thebearing surfaces of the second bearing assembly 200 b and/or in thefirst bearing assembly 100 b. Providing fluid flow through the grooves211 b may produce hydrodynamic operation of the bearing apparatus 300 b.For example, the fluid may be directed through the first bearingassembly 100 b and into the second bearing assembly 200 b (e.g., intothe grooves 211 b of the second bearing assembly 200 b). In anembodiment, the first bearing assembly 100 b may include an opening 109,which may pass through the first bearing assembly 100 b (e.g., throughsubstrate 130 b and/or through superhard body 120 b of the first bearingassembly 100 b). Particularly, the opening 109 may be in fluidcommunication with the grooves 211 b, and the fluid may pass through theopening 109 and into the grooves 211 b.

While the bearing assemblies and bearing apparatuses described above mayinclude support structures, it should be appreciated that this inventionis not so limited. For instance, FIG. 3D illustrates an embodiment of abearing apparatus 300 c that includes a first bearing assembly 100 c anda second bearing assembly 200 c assembled with one another, either orboth of which may not include a support structure. Except as describedherein, material, elements, or components of the bearing apparatus 300 cmay be similar to or the same as materials, elements, or components ofany of the bearing apparatuses 300, 300 a, 300 b (FIGS. 3A-3C).

In some embodiments, the first bearing assembly 100 c may include asuperhard body 120 c bonded to a substrate 130 c, which may besubstantially cylindrical. The first bearing assembly 100 c may besecured to or otherwise incorporated directly into moving (e.g.,rotating) or stationary machine component. Likewise, the second bearingassembly 200 c may include a hollow cylindrical or tubular superhardbody 220 c that may be bonded to a substrate 230 c. In some instances,the substrate 230 also may be at least partially tubular. The secondbearing assembly 200 c also may be directly attached to or incorporatedinto a moving (e.g., rotating) or stationary machine component. In anyevent, at least a portion of the superhard body 120 c may enter theopening in the superhard body 220 c.

Moreover, a bearing surface 110 c of the first bearing assembly 100 cmay engage a corresponding bearing surface 210 c of the second bearingassembly 200 c. For example, the bearing surfaces 110 c and 210 c mayhave an overlap 305 therebetween. In other words, the bearing surfaces110 c and 210 c may engage or at least partially contact each otheralong the overlap 305. For example, the overlap 305 may be greater thanor less than 0.50 inches, such as 0.3 inches to about 0.7 inches, 0.2inches to about 0.35 inches, or about 0.15 inches to about 0.30 inches.

The bearing apparatus 300 or any other bearing apparatus disclosedherein may be incorporated into any number of machines or mechanisms torotatably secure rotating components or elements thereof. FIG. 4illustrates an embodiment of a power generation unit 400 that includesthe bearing apparatus 300. In particular, the bearing apparatus 300 mayrotatably connect a shaft 410 within a housing 420. For example, thesecond bearing assembly 200 may be a stator and may be secured to and/orwithin the housing 420, such as to remain substantially stationaryrelative to the housing 420. The first bearing assembly 100 may be arotor and may be secured to the shaft 410 in a manner that allows thehousing 420 to rotate within the shaft 410. In an embodiment, the shaft410 may be secured within the section 141.

It should be appreciated that the first bearing assembly 100 may beattached to the shaft 410 in any number of suitable ways. In anembodiment, as noted above, the section 141 includes the opening 144that may accept a portion of the shaft 410. Moreover, the opening 144may position the first bearing assembly 100 relative to the shaft 410.For example, the opening 144 may align the first bearing assembly 100relative to the shaft 410, such that the first bearing assembly 100 isconcentric with the shaft 410. Accordingly, rotation of the shaft 410about center axis there may produce rotation of the first bearingassembly 100 about the axis 10.

Furthermore, the shaft 410 may be secured within the opening 144. Forexample, the opening 144 may include female threads that may engage withmale threads on an end of the shaft 410, thereby connecting the firstbearing assembly 100 to the shaft 410. In some instances, the threadsalso may align the first bearing assembly 100 relative to the shaft,such that the first bearing assembly 100 is concentric with the shaft410. Other fastening configurations (e.g., with screws) also may connectthe first bearing assembly 100 to the shaft 410. In additional oralternative embodiments, the shaft 410 may be press-fitted into theopening 144 of the first bearing assembly 100. Likewise, the firstbearing assembly 100 may be brazed, welded, or otherwise connected to orintegrated with the shaft 410 (e.g., the support structure 140 of thefirst bearing assembly 100 may be integrated with the shaft 410). In anyevent, the first bearing assembly 100 may be attached or secured to theshaft 410 in a manner that rotation of the shaft 410 produces acorresponding rotation of the first bearing assembly 100 and vice versa.

The term “housing” is not intended to be limiting and is provided onlyas an example component of the power generation unit 400. It should beappreciated that the shaft may be rotatably connected to any element orcomponent of a machine that may remain stationary relative to the shaftduring operation of such machine. In other words, the housing 420 may beany other stationary element or component that may secure a stator ofthe bearing apparatus 300, which may be rotatably engaged with a rotorof the bearing apparatus 300.

In an embodiment, the power generation unit 400 may include a turbine430 attached to the shaft 410. As fluid flows through the powergeneration unit 400 (as indicated by the arrows), the turbine 430 may beinduced to rotate together with the shaft 410. In an embodiment, thehousing 420 may include one or more openings, which may channel thefluid toward the turbine 430 and, subsequently, out of the powergeneration unit 400. The shaft 410 may be operably connected to analternator in a manner that rotation of the shaft 410 may drive thealternator (e.g., the shaft 410 may include a magnetic rotor that may besurrounded by windings), thereby converting mechanical energy intoelectrical power. Additionally, a portion of the fluid may be divertedor may otherwise flow between the first bearing assembly 100 and secondbearing assembly 200, as described above, thereby producing hydrodynamicoperation of the bearing apparatus 300.

It should be appreciated that any of the bearing apparatuses 300, 300 a,300 b, 300 c (FIGS. 3A-3D) may be used in the power generation unitdescribed above. Furthermore, even though the bearing apparatuses aredescribed above as used in a power generation unit (e.g., in the powergeneration unit 400), the embodiments of the invention are not solimited. Hence, any of the bearing apparatuses 300, 300 a, 300 b, 300 c(FIGS. 3A-3D) may be used in any suitable machine or mechanism tofacilitate rotation of one or more elements or components thereof. Forinstance, any of the bearing apparatuses 300, 300 a, 300 b, 300 c (FIGS.3A-3D) may be used a blood pump, such as a cardiopulmonary bypass bloodpump described in U.S. patent application Ser. No. 13/761,944, entitled“Bearing Assembly For Use In Axial-Flow Cardiopulmonary Bypass BloodPumps And Related Pumps,” filed on Feb. 7, 2013, the entire content ofwhich is incorporated herein by this reference. For instance, any of thebearing apparatuses 300, 300 a, 300 b, 300 c (FIGS. 3A-3D) may rotatablysecure the shaft of the blood pump within and relative to the housingthereof.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

I claim:
 1. A bearing apparatus, comprising: a first bearing assemblyincluding: a first support structure including a first recess; a firstsubstrate secured to the first support structure within the firstrecess; and a first polycrystalline diamond body bonded to the firstsubstrate at a bonding interface and protruding outward from the firstsupport structure, the first polycrystalline diamond body includingbonded diamond grains that define a convex radial-bearing surface, a topsurface, and a volume enclosed by the convex bearing surface, the topsurface, and the bonding interface, wherein the first bearing assemblyincludes one or more first thrust-bearing surfaces, and the top surfacedefines at least one of the one or more first thrust-bearing surfaces;and a second bearing assembly including a second polycrystalline diamondbody including bonded diamond grains and defining a concaveradial-bearing surface that is sized and configured to be positioned toat least partially contact the convex radial-bearing surface, the secondpolycrystalline diamond body defining one or more second thrust bearingsurfaces positioned and configured to engage the one or more firstthrust-bearing surfaces during use.
 2. The bearing apparatus of claim 1,wherein the second polycrystalline diamond body is bonded to asubstrate.
 3. The bearing apparatus of claim 1, wherein the firstradial-bearing surface is substantially continuous.
 4. The bearingapparatus of claim 1, wherein the second radial-bearing surface issubstantially continuous.
 5. The bearing apparatus of claim 1, whereinthe first radial-bearing surface defines an outside diameter, the secondradial-bearing surface defines an inside diameter, and a gap defined bythe difference between the outside diameter and the inside diameter isabout 2% to about 3% of the first outside diameter.
 6. The bearingapparatus of claim 1, wherein the first polycrystalline diamond bodyincludes a chamfer extending between the convex radial-bearing surfaceand a top surface of the polycrystalline diamond body.
 7. The bearingapparatus of claim 1, wherein the convex radial-bearing surface issubstantially cylindrical and the concave radial-bearing surface issubstantially cylindrical.
 8. The bearing apparatus of claim 7, whereinone or more of the convex radial-bearing surface or the concaveradial-bearing surface includes one or more grooves recessed therein. 9.The bearing apparatus of claim 1, wherein one or more of the firstpolycrystalline diamond body or the second polycrystalline diamond bodyhas a thickness that is less than 0.50 inches.
 10. The bearing apparatusof claim 1, wherein the convex radial-bearing surface and the concaveradial-bearing surface overlap by less than 0.50 inches.
 11. The bearingapparatus of claim 1, wherein the concave radial-bearing surface of thesecond polycrystalline diamond body defines an opening, and the secondbearing assembly includes a conduit in fluid communication with theopening.
 12. The bearing apparatus of claim 1 wherein the secondpolycrystalline diamond body includes a surface that circumscribes anopening at least partially defined by the concave radial-bearing surfaceand which defines one of the one or more second thrust-bearing surfaces.13. The bearing apparatus of claim 1 wherein the concave radial-bearingsurface of the second polycrystalline diamond body defines an opening,and the second polycrystalline diamond body is unitary and includes abottom surface defining a bottom of the opening in the second unitarypolycrystalline diamond body, and the bottom surfaces defines one of theone or more second thrust-bearing surface.
 14. An assembly, comprising:a housing; a first bearing assembly attached to the housing, the firstradial bearing assembly including a first unitary superabrasive bodyincluding bonded superabrasive grains and defining a convexradial-bearing surface and a top surface, the first bearing assemblyincluding one or more first thrust-bearing surfaces, at least one of theone or more first thrust-bearing surfaces being defined by the topsurface; a shaft rotatably secured within the housing; and a secondbearing assembly attached to the shaft, the second bearing assemblyincluding a second unitary superabrasive body including bondedsuperabrasive grains and defining a concave radial-bearing surface, theconcave radial-bearing surface being positioned to at least partiallycontact the first radial-bearing surface when the shaft rotates, thesecond unitary superabrasive body defining one or more secondthrust-bearing surfaces positioned to engage the one or more firstthrust-bearing surfaces when the shaft rotates.
 15. The assembly ofclaim 14, further comprising a turbine connected to the shaft in amanner that flow of fluid through the turbine produces rotation of theshaft.
 16. The assembly of claim 14, wherein the second bearing assemblyincludes a blind opening defined by the concave radial-bearing surfaceand by a bottom surface, the one or more second bearing-surfacesincluding the bottom surface.
 17. The assembly of claim 16, wherein thefirst unitary body of bonded diamond grains protrudes into the openingdefined by the concave radial-bearing surface.
 18. The assembly of claim17, wherein the concave radial-bearing surface is substantiallycylindrical and has an outside diameter about 0.23 inches to about 0.27inches.
 19. The assembly of claim 17, wherein the convex radial-bearingsurface is substantially cylindrical and has an inside diameter about0.23 inches to about 0.27 inches.
 20. The assembly of claim 14, furthercomprising: a first carbide substrate secured to a first supportstructure of the first bearing assembly, the first unitary superabrasivebody being bonded to the first carbide substrate; and a second carbidesubstrate secured to a second support structure of the second bearingassembly, the second unitary body of bonded diamond grains being bondedto the second carbide substrate.
 21. The assembly of claim 20, whereinone or more of the first carbide substrate is secured within a firstrecess of the first support structure or the second carbide substrate issecured within a recess of the second support structure.
 22. Theassembly of claim 14, wherein one or more of the unitary body of bondeddiamond grains and the another unitary body of bonded diamond grainshave a thickness of less than 0.50 inches.
 23. The assembly of claim 14,the convex bearing surface and the concave bearing surface overlap byless than 0.50 inches.